1. Field of the Invention
The invention relates to fuel supply installations for internal combustion engine and more particularly to a device for controlling the throttle member of the induction passage for such a carburation--or especially injection--installation.
2. Prior Art
At the present time, the tendency is to replace the control devices having a mechanical connection between the throttle member (or butterfly valve) and the control pedal with an electric connection. Devices are in particular known of the type comprising: a first electric sensor (generally a potentiometer) for recopying the position of the member actuated by the driver, an electric actuator and a second electric sensor both connected to the throttle member; and an electric circuit for energizing the actuator, receiving the output signal from the sensors and arranged so as to give the throttle member a position which depends on that of the drive actuated member.
The replacement of a direct mechanical connection with an electric circuit has the advantage of making it possible to make corrections which depend on different operating parameters of the engine, for example its speed and/or its temperature. In particular, it is possible to regulate the position of the throttle member during idling and to absorb the sudden movements of the member drive actuated member.
But most of existing devices have a grave defect: should the actuator fail, there is a danger that the throttle member remains open although the accelerator pedal is released.